Dual input, hot swappable dual redundant, enhanced N‘AC to DC power system

ABSTRACT

The inventive system uses modular N+1 bulk power supplies to power a computer system. Thus, the individual BPSs may be replaced while the system is on-line. Each BPS is split into two halves, with each halve being run by a separate power grid. This means that if one of the power grids goes down, the other grid fills the power. Thus, there are no switching times or latencies, the inventive power supply system keeps running. When both power grids are present, each power supply halve in a BPS load shares 50/50. The two input AC power grids are each controlled separately via two power distribution control assemblies (PDCA). Each assembly can be separately configured for 3 phase wye, 3-phase delta or single phase inputs.

BACKGROUND

[0001] Large, multi-processor computer systems are business enterpriseservers for use by large corporations with high speed computer needs,e.g. automotive companies, large accounting firms, Internet companies,etc. Enterprise servers take large amounts of AC current from the sitepower, typically on the order of 10-20 kilowatts of power. Therefore,3-phase power is usually used to power these systems. One of the majorrequirement for enterprise servers is what is called high availability.The meaning here is that there is the desire that there are no externalevents force the machine to crash. One common event that leads to asystem crash is loss of the system power. This may occur as a result ofa commercial power producer problem or it may originate with loss of asystem power component. Note that with three phase power, the problemcan be from the loss of the entire 3-phase grid, or loss of one of thethree legs.

[0002] To avert such failures, enterprise server customers generally tryto have an un-interruptible power supply or back-up motor generatorrunning their systems. In this case, the un-interruptible power supply,or UPS, is always online and of course, it too can fail. What wasneeded, then, was a different way to ensure availability andreliability.

[0003] One typical way is to have two power grids available for theproduct. One power grid could be the site 3-phase power, and the otherone could be an un-interruptible power supply or perhaps even a motorgenerator. Thus, when a failure is sensed on one of those power grids,an active switch mechanism changes the power feed to the computerproduct. In other words, if grid A failed, it would be sensed and grid Bwould be switched over into the machine. There are problems with thisapproach, primarily because the phase relationship between grid A andgrid B must be the same. Also, the tolerances of the power should alsobe the same, i.e. the power supplied by both grids should have the samevoltages and current levels. The biggest problem is that there is alatency time relating to that switchover. Thus, the computer may suffera power drop during switch over, and thus may crash. Systems with suchbackups are referred to as N+1 systems, the N being the required numberof power grids, the +1 being the backup grid.

SUMMARY OF THE INVENTION

[0004] These and other objects, features and technical advantages areachieved by a system and method which uses modular N+1 power sources.Thus, the individual power supplies, or bulk power supplies (BPSs) maybe swapped out of the computer. The BPSs supply power to the computercomponents. The power supply system uses a plurality of BPSs accordingto an N+1 requirement. For example, if 5 BPSs are required to run thecomputer system, then 6 BPSs would be installed in the power supplysystem. Thus, if one BPS goes down, the remaining five can satisfy thesystem's power needs. This also allows the BPSs to be hot swappable,meaning that a BPS can be changed for a new one, without shutting thesystem down. This allows for the system to be repaired, e.g. defectiveBPSs can be swapped, or upgraded, e.g. a newer model replaces an olderone. This also allows for repairs or modifications to be performed whilethe system is running, e.g. one BPS is pulled for repair/modification,while the other BPSs provide power to the system.

[0005] Each BPS is split into two halves, with each halve being run by aseparate power grid. This means that if one of the power grids goesdown, the other grid fills the power. Thus, there are no switching timesor latencies, the inventive power supply system keeps running. When bothpower grids are present, each power supply halve in a BPS load shares50/50. To make this possible, it was necessary to be able to accommodatetwo input power grids of basically any voltage between 176 and 284 VAC.The phase relationship of these voltages is unimportant.

[0006] The two input AC power grids are each controlled separately viatwo power distribution control assemblies (PDCA). Each assembly can beseparately configured for 3 phase wye or 3-phase delta inputs. Each PDCAcan also be separately configured to receive single phase power. EachPDCA divides the power among the BPSs. The wiring blocks used toconfigure the PDCA for any 3 phase wye, 3-phase delta inputs, or singlephase are field configurable, and can be changed out to permit adifferent power input. Thus, if one power grid or PDCA goes down, theBPSs will pull their power needs from the other PDCA and grid. Thus, ifone PDCA goes down, the remaining one can satisfy the system's powerneeds. This also allows the PDCAs to be hot swapped, meaning that a PDCAcan be changed for a new one, without shutting the system down. Thisallows for the system to be repaired, e.g. defective PDCAs can beswapped, or upgraded, e.g. a newer model replaces an older one. Thisalso allows for repairs or modifications to be performed while thesystem is running, e.g. one PDCA is pulled for repair/modification,while the other PDCA provides power to the system.

[0007] Therefore, it is a technical advantage of the present inventionto be able use any form of power to supply the computer system, e.g.3-phase delta power, 3-phase wye power, single phase power, motorgenerated power, or UPS power. Any of these configurations can beaccommodated as either the primary and/or the backup power source.

[0008] It is another a technical advantage of the present invention tobe able have a two way redundant power supply. One is AC input powerredundancy, via two PDCAs. The other is DC power redundancy, via N+1BPSs.

[0009] The foregoing has outlined rather broadly the features andtechnical advantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present invention. It should also be realized by thoseskilled in the art that such equivalent constructions do not depart fromthe spirit and scope of the invention as set forth in the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWING

[0010] For a more complete understanding of the present invention, andthe advantages thereof, reference is now made to the followingdescriptions taken in conjunction with the accompanying drawing, inwhich:

[0011]FIG. 1 depicts a functional block diagram for the preferredembodiment of the inventive power supply system;

[0012]FIG. 2 depicts the functional block diagram for the preferredembodiment of a bulk power supply;

[0013]FIG. 3 depicts the functional block diagram for the preferredembodiment of a bulk power supply connection;

[0014]FIGS. 4A and 4B depict the wiring for three phase delta powerinput; and

[0015]FIGS. 4A and 5B depict the wiring for three phase wye power input.

DETAILED DESCRIPTION

[0016]FIG. 1 depicts a functional block diagram for the preferredembodiment of the inventive power supply system 100. In this system, sixbulk power supplies (BPSs) 101 are used. Note that this number is forillustration only, as more or fewer BPSs could be used, as long as thereare N+1 present. Each BPS receives power via a connecting backplane orchassis 102 The chassis 102 is connected to two power grids, 103, 105via power distribution control assemblies (PDCAs) 104, 106. Note thateach PDCA 104, 106 is feeding each BPS 101. The BPSs 101 form a 48-voltand a 5-volt DC outputs, which are provided back to the chassis 102 fordistribution to other components of the system, e.g. the main computerprocessor boards, via buses 107, 108. Note that the voltage levels andthe number of levels is by way of example only, as system requirementsmay have different voltage levels as well as a different number oflevels.

[0017] The PDCAs 104, 106 can be field-configured to accept 3-phasedelta, 3-phase wye, or single phase as the power source, depending onthe grid 103, 105 being used. The phase legs of the three phase inputsare arranged such that legs, L1, L2, and L3, each feeds two BPS slots.Each BPS receives an input from each PDCA. Thus, a power loss from oneof the PDCAs would only disable one-half of each BPS. Each BPS isconnected to a power monitor (301 of FIG. 3) via control signals 106.These signals allow for each BPS to be powered up/down, as wells as sendand receive status information. 5VHK J2 108 is a +5 volt DC output usedfor end-system housekeeping (HK).

[0018]FIG. 2 depicts the functional block diagram for the preferredembodiment of a BPS 101. The BPS includes line filter blocks 201, 202and rectifier blocks 213, 216 that receive the two AC inputs. The EMIfilter portion suppresses harmonic signals from reflecting back into theAC input lines. The rectifier blocks rectify the AC input power into DCpower. The filtered DC output is provided to PFC blocks 214, 217 whichensure a power factor of greater than about 0.98. Their outputs areprovided to converters 203/204 for the +48 voltage level and 205 for the+5 volt level. The outputs of the converters are sent to isolationdiodes/output filters 206. The isolation diodes are necessary for hotswapping and the output filter elements are capacitors. The BPS usesfans 207 to cool the BPS. Bias supplies 215, 219 supply power to thefans 207 and the control logic 209. Output terminals 211 receives the 48volt output from the filter 206, which is then delivered back to thechassis 102. Output connector 212 receives the 5 volt output from thefilter 206, which is then delivered back to the chassis 102. Load sharecontroller 208 operates to control load sharing of the +5VHK. Controllogic 209 controls the other elements of the BPS, as well assends/receives status information to/from the power monitor 301 viaconnector 210. Substantially instantaneous switching without using aswitch is accomplished by having two converter chains (i.e. 201, 213,214, 203; and 202, 216, 217, 204). If one chain should drop off, theother chain sees a higher load, and then increases its power output. Inother words, each chain is capable of fully satisfying the load for theBPS.

[0019]FIG. 3 depicts the functional block diagram for the preferredembodiment of a BPS 101 connects with PDCAs 104, 106. The power monitor301 receives AC status information 302, BPS status information 303, aswells as send commands to the BPSs via 303. The power monitor is aconsumer of the 5 volt power supply from 108. Note that the monitor 301is not part of the BPS or power supply system, but rather is part ofend-product computer system. In the depicted example, the PDCAs areprovided with 3 phase AC power, which they convert into three singlephase pairs. PDCA 104 (shown for delta connection) provides input pairsA1, A2, A3, and ground to the BPSs. PDCA 106 provides input pairs B1,B2, B3, and ground to the BPSs. The As and Bs are two wire pairs of ACpower. Each input signal feeds two BPSs, if there are more/fewer BPSs,then each input signal would feed more/fewer BPSs. In the depictedexample, the A1 pair goes to BPS slots 0 and 1, the A2 pair goes to BPSslots 2 and 3, and the A3 pair goes to BPS slots 4 and 5. Similarly, theB1 pair goes to BPS slots 0 and 1, the B2 pair goes to BPS slots 2 and3, and the B3 pair goes to BPS slots 4 and 5. Note that this is forillustration purposes only, as different pairs of As and Bs could feeddifferent BPS slots. Each PDCA contains wiring to convert the threephase input into three single phase outputs, where the legs, L1, L2, L3of the three phase input are wired to the outputs A1, A2, A3, B1, B2,and B3 as follows: A1 A2 A3 3 phase delta L1-L2 L2-L3 L3-L1 3 phase wyeL1-N L2-N L3-N B1 B2 B3 3 phase delta L1-L2 L2-L3 L3-L1 3 phase wye L1-NL2-N L3-N

[0020]FIG. 4A depicts the wiring and slot load scheme for three phasedelta power input. FIG. 4B depicts the wiring block for the three phasedelta power input. Pair 1 corresponds to A1 or B1, pair 2 corresponds toA2 or B2, and pair three corresponds to A3 or B3. Thus, the PDCA wiresBPS slots 0 and 1 to a single-phase pair that is formed from L1 and L2,BPS slots 2 and 3 of the BPS are single-phase pair formed from L2 andL3, and BPS slots 4 and 5 are single-phase pair formed from L1 and L3.FIG. 5A depicts the wiring and slot load scheme for three phase wyepower input. FIG. 5B depicts the wiring block for the three phase wyepower input. Pair 1 corresponds to A1 or B1, pair 2 corresponds to A2 orB2, and pair three corresponds to A3 or B3. Thus, the PDCA wires BPSslots 0 and 1 to a single-phase pair that is formed from L1 and neutral(N), BPS slots 2 and 3 of the BPS are single-phase pair formed from L2and N, and BPS slots 4 and 5 are single-phase pair formed from L3 and N.

[0021] The wiring blocks of FIGS. 4B and SB can be hard wired into thePDCAs or the blocks can be formed as a programming plug which isinserted into a socket in the PDCAs, each socket would have connectionsfor L1, L2, L3, G, 1, 2, 3, 4, 5, 6, and G. Thus, to changeconfigurations, the current plug is removed and a different plug isinserted into the socket.

[0022] Although the invention has been described in terms of three phasepower grids, 103, 104. These grids could either or both be large singlephase grids. In that case, the wiring in the PDCA would be a 6 way splitof the input power grid, with one line to each slot.

[0023] Although the present invention and its advantages have beendescribed in detail, it should be understood that various changes,substitutions and alterations can be made herein without departing fromthe spirit and scope of the invention as defined by the appended claims.Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present invention, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present invention. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

What is claimed is:
 1. A bulk power supply providing a supply poweroutput for a user system comprising: a first converter subsystem thatreceives AC power from a first grid and is capable of producing a firstpower output; and a second converter subsystem that receives AC powerfrom a second grid and is capable of producing a second power output;wherein if the first and second converter subsystems are operating, thenthe supply power output is equal to approximately one half of the firstpower output plus approximately one half of the second power output;wherein if one of the first converter subsystems fails, then the supplypower output is equal to the second power output.
 2. The bulk powersupply of claim 1 wherein each converter subsystem comprises: a linefilter that prevents signals from being reflected back in the grid; arectifier for converting the AC power to DC power; a power factorcorrection to ensure the DC power has at least a predetermined value forpower factor; and a DC converter that receives the corrected DC powerand produces an output that is at a level usable by the user system. 3.The bulk power supply of claim 1 wherein the bulk power supply is one ofa plurality of bulk power supplies; the plurality of bulk power suppliesis equal to N+1, wherein N is the number of bulk power supplies requiredto supply the user system; and whereby a failure of one bulk powersupply will permit the remaining bulk power supplies to provide power tothe user system.
 4. The bulk power supply system of claim 3 wherein:each bulk power supply may be replaced while the user system is on-line.5. A bulk power supply system providing power for a user system,comprising: a plurality of bulk power supplies each of which produces asupply power output; and a plurality of power grids, with each gridconnected to each of the bulk power supplies, and supplying input ACpower to each of the bulk power supplies; wherein if all of the gridsare operating, then each bulk power supply is receiving a first equalfraction of their respective input AC power from each of the grids andis producing the supply power output from the first equal fraction;wherein if one of the grids fails, then each bulk power supply isreceiving a second equal fraction of their respective input AC powerfrom each of the remaining grids and is producing the supply poweroutput from the second equal fraction.
 6. The bulk power supply systemof claim 5 wherein each converter subsystem comprises: a line filterthat prevents signals from being reflected back in the grid; a rectifierfor converting the AC power to DC power; a power factor correction toensure the DC power has at least a predetermined value for power factor;and a DC converter that receives the corrected DC power and produces anoutput that is at a level usable by the user system.
 7. The bulk powersupply system of claim 5 wherein: the plurality of bulk power suppliesis equal to N+1, wherein N is the number of bulk power supplies requiredto supply the user system; whereby a failure of one bulk power supplywill permit the remaining bulk power supplies to provide power to theuser system.
 8. The bulk power supply system of claim 7 wherein: eachbulk power supply may be replaced while the user system is on-line. 9.The bulk power supply system of claim 5 wherein: the plurality of powergrids is equal to two grids; the first equal fraction is one half; andthe second equal fraction is one.
 10. The bulk power supply system ofclaim 5 further comprising: a plurality of power distribution controlassemblies, with one assembly associated with each grid; wherein eachpower distribution control assemblies receives one of three phase deltapower, three phase wye power, and single phase power from its associatedgrid and distributes the power to each of the plurality of bulk powersupplies.
 11. The bulk power supply system of claim 5 wherein one of thereceived power is three phase delta, and the associate powerdistribution control assembly comprises: a wiring block that providesL1-L2 to a first portion of bulk power supplies, L2-L3 to a secondportion of bulk power supplies, and L3-L1 to a third portion of bulkpower supplies.
 12. The bulk power supply system of claim 5 wherein oneof the received power is three phase wye, and the associate powerdistribution control assembly comprises: a wiring block that providesL1-N to a first portion of bulk power supplies, L2-N to a second portionof bulk power supplies, and L3-N to a third portion of bulk powersupplies.
 13. The bulk power supply system of claim 5 wherein one of thereceived power is single phase, and the associate power distributioncontrol assembly comprises: a wiring block that provides the singlephase of received power to each of the bulk power supplies.
 14. A powerdistribution control assembly that receives one of three phase deltapower, three phase wye power, and single phase power from a power gridand distributes the power to each of a plurality of bulk power supplies,the assembly comprising: a plurality of input terminals that areconnected to the power grid; a wiring block that is connected to theinput terminals and divides the power from the power grid based upon thenumber of bulk power supplies and the phase of the power; a plurality ofoutput terminals that receive the divided power and provides the dividedpower to the plurality of bulk power supplies.
 15. The powerdistribution control assembly of claim 14 wherein: the received power isthree phase delta; and the wiring block provides L1-L2 to a firstportion of bulk power supplies, L2-L3 to a second portion of bulk powersupplies, and L3-L1 to a third portion of bulk power supplies.
 16. Thepower distribution control assembly of claim 14 wherein: the receivedpower is three phase wye; and the wiring block that provides L1-N to afirst portion of bulk power supplies, L2-N to a second portion of bulkpower supplies, and L3-N to a third portion of bulk power supplies. 17.The power distribution control assembly of claim 14 wherein: thereceived power is single phase; and the wiring block that provides thesingle phase of received power to each of the bulk power supplies.